﻿using System;
using System.Collections.Generic;
using System.Web;
using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

/// <summary>
/// *========================
///  图片操作助手类
///  V1.0.100429 (CMS7)
///  by eXplorer
/// *========================
/// </summary>
namespace CMS.Helper
{
    public sealed class ImageHelper
    {
        public ImageHelper()
        {
            //
            //TODO: 在此处添加构造函数逻辑
            //
        }

        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式</param>    
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            Image originalImage = Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;

            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形）                
                    break;
                case "W"://指定宽，高按比例                    
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）                
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片
            Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充
            g.Clear(Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
                new Rectangle(x, y, ow, oh),
                GraphicsUnit.Pixel);

            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }

        /// <summary>
        /// 调整图片分辨率
        /// </summary>
        /// <param name="orgImgPath">原图路径[绝对]</param>
        /// <param name="toWidth">目标宽度</param>
        /// <param name="toHeight">目标高度</param>
        /// <param name="outputFolder">输出路径[绝对]</param>
        /// <param name="outputFileName">输出文件名</param>
        /// <returns></returns>
        public static bool ResizeImage(string orgImgPath, int toWidth, int toHeight, string outputFolder, string outputFileName)
        {
            try
            {
                byte[] zp = Load_pictMemory(orgImgPath);
                MemoryStream ms = new MemoryStream(zp);
                System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
                Bitmap btp = new Bitmap(img, toWidth, toHeight);
                DirectoryInfo dti = new DirectoryInfo(outputFolder);
                FileInfo[] fis = dti.GetFiles();
                string targetFile = outputFolder + "\\" + outputFileName;
                if (File.Exists(targetFile))
                {
                    IOHelper.DeleteFile(targetFile);
                }
                btp.Save(targetFile);
                return true;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }

        /// <summary>
        /// 加载图片数据流
        /// </summary>
        private static byte[] Load_pictMemory(string filePath)
        {
            byte[] pictData = null;
            FileInfo fi = new FileInfo(filePath);
            if (fi.Exists)
            {
                pictData = new byte[fi.Length];
                FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite);
                BinaryReader br = new BinaryReader(fs);
                br.Read(pictData, 0, Convert.ToInt32(fi.Length));
                fs.Dispose();
            }
            else
            {
                HttpContext.Current.Response.Write("<script language='javascript'>alert('没有找到你所指定的图片')</script>");
            }
            return pictData;
        }

        /// <summary>
        /// 图片加水印
        /// </summary>
        /// <param name="strText">水印文本</param>
        /// <param name="orgImgPath">原图路径[绝对]</param>
        /// <param name="outImgPath">目标路径[绝对]</param>
        /// <returns>是否成功</returns>
        public static bool AddWaterMark(string strText, string orgImgPath, string outImgPath)
        {
            try
            {
                Image myimage = Image.FromFile(orgImgPath);
                Graphics g = Graphics.FromImage(myimage);
                g.DrawImage(myimage, 0, 0, myimage.Width, myimage.Height);
                Font f = new Font("Verdana", 10);
                Brush b = new SolidBrush(Color.LightSlateGray);
                g.DrawString(strText, f, b, myimage.Width - 100, myimage.Height - 20);
                g.Dispose();
                myimage.Save(outImgPath);
                myimage.Dispose();
                return true;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }

        /// <summary>
        /// 获取图片分辨率
        /// </summary>
        /// <param name="imgPath">图片路径[绝对]</param>
        /// <returns>图片分辨率</returns>
        public static int[] GetResolutionRatio(string imgPath)
        {
            try
            {
                Image img = Image.FromFile(imgPath);
                int imgWidth = img.Width;
                int imgHeight = img.Height;
                int[] result = { imgWidth, imgHeight };
                return result;
            }
            catch (Exception)
            {
                int[] result = { 0, 0 };
                return result;
            }
        }
    }
}